The two ends of the first arc-shaped guide pin (12) are respectively sleeved in the through holes (51) so as to create an interference fit between the magazine cover shell (1) and the positioning sleeves (5).
The restraint (5) has a guide piece (16) with a slanted surface (17) and a guide pin (15) which is guided thereon.
The blade (30b) has a guide groove (37b) engaged with the guide pin (17b) and is rotatably fitted to the drive pin (59b) so as to be rotatable about the drive pin (59b).
Each of the bridge portions includes a guide pin hole.
Aligning is performed by fitting the guide pin (9) of the optical connector (10) in a guide hole (8) on the photoelectric conversion module (14).
In one embodiment of the invention, the no-return mechanism comprises: a ribbed surface deployed along the interior wall of the tube; and at least one dowel attached to the piston correspondingly to the ribbed surface.